Iris Vs Shutter Speed

Author: John Honovich, Published on Jan 24, 2013

Surveillance cameras must deal with wide variations of lighting -- automatically and continuously. It can be 10,000+ lux during the day and under 1 lux at night. In a few seconds, lighting can drop dramatically, for example, if the sun goes behind a cloud or if a person turns off the lights. As lighting changes, the camera needs to adjust on its own without having a photographer optimize the scene.

Surveillance cameras do this through two means - controlling the size of the iris or the speed of the shutter. Indeed, often cameras can control both simultaneously. In this tutorial, we compare the two and explain how they relate.

*** **********, *** ******* ****************** *************.

Controlling ***** *****

******* *** **** "**********" - **** ****** **** **** *** little ** *** **** *****, ** ***** ** ** **** right.

exposure contrast

** ******, *** ****** ** ***** **** ** '**** *****' for * ****** ******* ** *** **** ***** ** ** the *****. ** *** ******* *****, ** *** ****** **** open, *** ***** ***** **** *** **** ***** *** *** camera ***** **** ** ****** ** **** .

Two "********"

***** ** ******* *** ***** **** ***** ** * ****. If *** **** ** ******* *** ***** *** *** ** it *** ****:

  • **** *** **** ****** (** *******); *** *******, **** ** adjusting ******* ****
  • **** *** **** ****** (** *******); *** *******, **** ** adjusting ********** *****

Why *** **. *** *****

**** ******* (***** ** ****** **** ****) **** ****** ** adjusting *** ******* *****. *****'* ** ****** ****.

***** ******* (**** ** * **** ****) *** **** *** iris **** *********** ****** ** *******. ** ********, *********, **** will **** ** **** ** ******* *** ******* ***** ** well.

*** **** ********** ** **** *** ******* ****** *** ****** limitless ***** **** *** * **** ******** **********. *** *** only **** *** **** ** **** ***** *** **** ********** cannot ******* ******** ****. *******, *** ******* *** ** **** to **** **** *** ** **** ** *** ****** ************ (and ****) *******. ***** **** **** ***** *** **** ***** and * *** ******** ******* ** **** **********, ** *** also****** ******* ************ ***** ****** ******* *******.

** *** ***** ****, *********** *** **** *** ***** *** a ****** ***** ** ****. *******, **** *** ******* ********* benefit ** ************ *** **** *** **** ** **** ********** because *** ****** * ***** ******** ** ** **** **** make *** ***** **** *** *******. *** ******** ** ***** ********.

Practical ******

*** ****-*****. ******** ****:

  • ******* **** ** ************* *** ************ ******** *** ****** ** light **** ******
  • **** *** ** **** ** ********* *** ***** ** *** opening *** ***** (****) ** *** ****** ** **** ***** enters (*******)
  • ******* ******** ***** *********** *** ********** *** ******* ** **** of ***** *** **** *** **** ** ********
  • **** ******** *** ********* *** ****** *** *** ** ** neither ********* *** ********* *** **** ************ ************
Login to read this IPVM report.
Why do I need to log in?
IPVM conducts unique testing and research funded by member's payments enabling us to offer the most independent, accurate and in-depth information.

Related Reports

Building Occupancy Codes and Access Control Tutorial on Nov 01, 2018
A building or room's classification can greatly impact which building codes must be followed. In terms of access control, these 'occupancy codes'...
AHJ / Authority Having Jurisdiction Tutorial on Sep 27, 2018
One of the most powerful yet often underappreciated characters in all of physical security is the Authority Having Jurisdiction (AHJ). Often,...
IP Camera Cable Labeling Guide on Sep 14, 2018
Labeling cables can save a lot of money and headaches. While it is easy to overlook, taking time to label runs during installation significantly...
Drain Wire For Access Control Reader Tutorial on Sep 04, 2018
An easy-to-miss cabling specification plays a key role in access control, yet it is commonly ignored. The drain wire offers protection for readers...
Exit Devices For Access Control Tutorial on Aug 28, 2018
Exit Devices, also called 'Panic Bars' or 'Crash Bars' are required by safety codes the world over, and become integral parts of electronic access...
Inputs/Outputs For Video Surveillance Guide on Aug 24, 2018
While many cameras have Input/Output (I/O) ports, few are actually used and most designers do not even consider them. However, a good understanding...
Backup Power for Large Security Systems Tutorial on Aug 24, 2018
Choosing the right backup power system depends on system size. While small and medium systems greatly benefit from using UPS battery backup...
Backboxes for Video Surveillance Tutorial on Aug 15, 2018
Backboxes are a necessity in surveillance, whether for managing cable whips, recessing cameras, adding wireless radios. But it can be confusing to...
Camera Focusing Tutorial on Aug 09, 2018
A camera's focus is fundamental to quality imaging. Mistakes can cause important problems. In this guide, we explain focus issues and proper...
Installing Surveillance Cameras Into Synthetic Stucco (EIFS) Tutorial on Jul 30, 2018
Mounting cameras into synthetic stucco, commonly known as EIFS finishes, can be problematic If not properly planned, EIFS/stucco can be downright...

Most Recent Industry Reports

Imperial Capital Security Investor Conference 2018 Review - ADT, Resideo, Alarm.com, Arlo, Eagle Eye, ACRE, More on Dec 14, 2018
Imperial Capital Security Investor Conference is an event matching industry executives with financiers that frequently leads to future funding...
Cisco Meraki New Cameras and AI Analytics on Dec 14, 2018
Meraki has released their second generation of video surveillance with 3 new cameras, AI-based video analytics, and 2 cloud-based storage...
Foolish Strategy: OEMing Facial Recognition on Dec 13, 2018
Almost as 'hot' as face recognition marketing right now is OEMing facial recognition. Last year, they were a who's who of company's with...
DVR Examiner - Video Recovery from Recorder Hard Drives on Dec 13, 2018
Bypassing passwords and long download times on-site, DVR Examiner collects and organizes video evidence directly from a hard drive extracted from...
2019 Access Control Book Released on Dec 12, 2018
This is the best, most comprehensive access control book in the world, based on our unprecedented research and testing has been significantly...
Huawei Hisilicon Quietly Powering Tens of Millions of Western IoT Devices on Dec 12, 2018
Huawei Hisilicon chips are powering, at least, tens of millions of Western IoT devices, such as IP cameras and surveillance recorders, a fact that...
FLIR Launches Body Cameras Unified With VMS (TruWitness) on Dec 11, 2018
While FLIR is best known for their thermal cameras, now they have expanded into body cameras, launching TruWITNESS, a public safety focused body...
Startup Sunflower Labs' Autonomous Drone Security System on Dec 11, 2018
Startup Sunflower Labs is claiming a unique design on a home security system, combining autonomous drones and 'Sunflower' sensors. Imagine an...
The 2019 Video Surveillance Industry Guide on Dec 10, 2018
The 300 page, 2019 Video Surveillance Industry Guide, covers the key events and the future of the video surveillance market, is now available,...
Multi-Factor Access Control Authentication Guide on Dec 10, 2018
Can a stranger use your credentials? One of the oldest problems facing access control is making credentials as easy to use as keys, but restricting...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact